How to integrate woocommerce with ionic App?

Any one can integrate woocommerce with ionic app.How to implement that integration?

Yes indeed you can. You need to use the woocommerce rest api here

could you give some suggesstion how to integrate the api key inside the ionic app

You need get a clientID and clientSecret from Woocommerce and secure store them in your application. From there you would use something along the lines of the lines of code below before you do any operation with the rest api.

    this.headers = new Headers();
    this.headers.append('Content-Type','application/json');
    this.headers.append('Authorization', "Basic " + btoa(clientID + ":" + clientSecret));